A STRANGE-LOOKING plant growing by the track edge on Hillfoot Hill above Dollar caught my eye, which exhibited spherical seedheads covered in reddish spines.

It caused a bit of head-scratching because I was unsure of its identity and was unlike any wild plant I had come across before in Scotland.

Some research revealed the plant's identity as the delightfully named piri-piri burr, an invasive non-native species which hails from New Zealand.

It was first recorded in the UK in 1901 and was most-likely introduced here on the fleeces of sheep imported from New Zealand.

Piri-piri is a small shrubby plant, which produces balls of reddish flowers in late spring which ripen into red, barbed fruits, called burrs which turn brown during the summer.

The barbed burrs detach from the plant in mid to late summer onto anything that passes – boot laces, socks, dogs and livestock, and thus the plant is easily spread.

In some parts of the country it is deemed a pest because it forms dense mats which often results in the loss of native plants where it grows.

It is just one more non-native in a long list of plants that inhabit the Clackmannanshire countryside.

Many – such as monkeyflower along the River Devon – are benign in their environmental impact, but others, such as Himalayan Balsam and Japanese knotweed cause real problems and are very difficult to control.

One attractive native species that has been catching my eye by the River Devon near Dollar at the moment is giant bellflower – a relative of the harebell.

They've colonised this stretch of the river only comparatively recently, and are much more frequently encountered further upstream in the shady woods of the Devon Gorge.

I suspect floodwaters have carried their seeds downstream to colonise new areas.

They can grow to more than a metre in height and their large lilac flowers are most attractive.